This invention relates to telescopic sights and more particularly to a telescopic sight which can be employed for either nighttime or daytime operation and which is particularly adaptable for application on weapons ranging from rifles to anti-tank weapons. When not mounted to a weapon, the sight may be used for observation purposes.
There currently exists an abundance of devices for aiming a weapon which are generally designated as sights. In general a sight is utilized for aiming a weapon during daytime operation at a directly visible target and during nighttime operation at a target which is only visible through the use of some vision aiding device.
Daytime sight devices range from simple front and rear sights like those on ordinary rifles to complex systems for large weapons. The sighting devices are mounted to a weapon and boresighted to that weapon for accurate aiming.
Certain sophisticated types such as telescopes are utilized to magnify a target and to enable the user during normal daytime operation to view a magnification of the target area at which he is aiming.
There are also nighttime vision devices or sights which employ image intensifiers or similar structures. The function of an image intensifier is to multiply the amount of incident light received by it to produce a signal that is bright enough for presentation to the eyes of a viewer. As such, these devices have been employed by the military and in commercial devices as well. Sights vary in size, magnification, type of reticle, weapon application and level of performance.
Several combination day/night weapon sights are known. One type of sight employs a modular configuration as is shown in U.S. Pat. No. 4,822,994. In this configuration, the front end of a telescopic sight is separable from the rest of the sight. For nighttime use an image intensifier module is inserted between the sections. However, for daytime operation, the user must disassemble the sight and remove and store the image intensifier module.
U.S. Pat. No. 4,629,295 is directed to another type of night viewing device which is an add-on accessory to day rifle sights. This device is attached directly to the day rifle scope. It includes an objective assembly which receives the image and directs it to a night vision device. The intensified image is then directed to the day sight for viewing. Again, the device is bulky and must be carried by the user or stored during daytime operations.
One disadvantage to having separate daytime and nighttime sights is that the sights must be individually boresighted to the weapon whenever the sight is initially installed, and must be checked for boresight whenever the sight is reinstalled on the weapon. Current use of weapon sights by law enforcement and military personnel and by civilian users involves the careful mounting and boresighting of a day and/or night vision sight to the weapon. For maximum accuracy, actual firing of the weapon is required during the boresighting process. This is not generally feasible under combat conditions. Separate weapon sights are also disadvantageous because the sights must be interchanged for day or night use. In addition, the separate night vision sight adds an additional three to four pounds which must be carried and handled separately by the user.
Another type of sight employs an integral configuration in which both day and night devices form part of the sight. In this sight, a plate carrying both day and night optical systems is rotated to position the day or night optical system to be used in the optical path, i.e. in the line of target sighting. This configuration usually takes more space and has a greater total weight than the separate systems it replaces.
It is therefore an object of the present invention to provide a telescopic sight which has an integral day/night viewing system.
It is another object of the present invention to provide a day/night telescopic sight for which boresighting is performed only once without the need for separate boresighting for day or night use.
It is still an additional object of the invention to provide a day/night telescopic sight which is light in weight, has a low profile configuration and is simple to operate.
It is an additional object to provide a day/night weapon sight which can be employed in a variety of sizes for application on weapons ranging from rifles to machine guns, grenade launchers, anti-tank weapons and the like.